TW201804640A - Display device manufacturing method - Google Patents

Abstract

To provide a display device that can be bent using a simple method without peeling an organic resin film and a glass substrate from each other. A display device manufacturing method, including: a step for forming a polyimide film 12 on a first main surface of support glass 20; a step for forming a display element including a transparent electrode layer 14 and a light-emitting layer 16 on the polyimide film 12; and a step for etching, while covering the first main surface side of the support glass 20 including the polyimide film 12 with a protective film 22, the second main surface side and thereby removing the support glass 20.

Description

Display device manufacturing method

The present invention relates to a method for manufacturing a display device such as an organic EL display, and more particularly, to a method for manufacturing a thin and flexible display device.

Conventionally, a display device using a flat panel display such as a liquid crystal display or an organic EL display has been used in various applications. In particular, in recent years, from the viewpoint of design, flexible displays have attracted much attention. When manufacturing a flexible display, an organic EL display that can easily cope with bending is often used.

A conventional organic EL display uses a glass substrate such as a cap glass to seal a display element such as an organic EL element. The glass substrate maintains the airtightness and watertightness of the organic EL element, and prevents the element from being deteriorated due to oxygen or moisture. However, organic EL displays using resin substrates have been developed in recent years in response to requirements for thinner thicknesses or bending as described above. Compared with glass substrates, resin substrates are more flexible, and are less likely to break even if they are bent. By using a laminated structure of an inorganic film and an organic film, the display element is sealed, thereby achieving the same level of gas resistance as the glass substrate. Obstacle.

However, forming a thin-to-bend resin substrate is very difficult to handle in a manufacturing process, and as a result, the yield may be deteriorated. Therefore, conventionally, an organic resin film such as polyimide was formed on a supporting glass, which facilitated handling during manufacturing processes. In a state where the rigidity of the entire substrate is secured by the supporting glass, a display element such as a functional film is formed on the organic resin film, and after the sealing process is performed, the organic resin film is peeled from the supporting glass (see, for example, Patent Document 1). The operation of peeling the organic resin film from the support glass is performed by removing a release layer formed between the support glass and the organic resin film in advance by a laser device.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-004112

However, in the above method, there is a possibility that the laser light is irradiated when the supporting glass is peeled off, which may adversely affect the display element. In addition, expensive manufacturing equipment such as excimer lasers must be introduced, which also consumes production costs. In particular, in recent years, a large substrate and a plurality of display devices are produced in a chamfered state. However, the larger the substrate, the larger the laser irradiation area. Therefore, there are many cases where the production efficiency is lowered or defective peeling occurs.

An object of the present invention is to provide a display device that can be bent in a simple manner without the need for a peeling process between an organic resin film and a glass substrate.

The method for manufacturing a display device of the present invention includes: a step of forming an organic resin film on a first main surface of a glass substrate; a step of forming a layer including a display element on the organic resin film; A step of removing the glass substrate by etching the second main surface side of the glass substrate of the resin film on the first main surface side.

In the process of forming an organic resin film on a glass substrate, for example, a conventionally used supporting glass is coated with an organic resin film using a coating device such as a slit coater. For the organic resin film, polyimide is preferably used. In the process of forming a display element, a functional layer including a light-emitting layer such as a thin-film transistor or an organic EL is formed on an organic resin film. After the display element as described above is formed, it is sealed so that the display element is not exposed to outside air. In the sealing process, a sealing process by a resin film formed by alternately laminating an inorganic film and an organic film is performed. After the sealing treatment, the resin film is coated with a thin film or a resist material having an etching resistance, and the glass substrate is etched. In the etching process, a thinning process is performed by contacting the etchant with the glass substrate from the second main surface side. In principle, the glass substrate is removed by etching until the glass substrate is completely dissolved. However, there are cases where the glass substrate is peeled off properly during the dissolution of the glass substrate. In the case shown above, the glass substrate can be removed even if the glass substrate is not necessarily completely dissolved.

The present invention is characterized in that all of the glass substrate is dissolved by an etching process. The etching process uniformly dissolves the entire surface of the glass substrate, so that even if the substrate size is increased, there will be no reduction in production efficiency. shape. In addition, since the etching process is performed under proper protection of the display element, there is no risk of deterioration of the display element, and a flexible display can be manufactured.

In addition, when etching a glass substrate, it is preferable to use an etching solution in which the glass substrate is soluble but the organic resin film is not soluble. With this configuration, even if the glass substrate is completely dissolved and the organic resin film is exposed, the organic resin film is not stained by the etching solution. As the etching solution, it is preferred to use a hydrofluoric acid-containing solution.

According to the present invention, there is provided a display device that can be easily bent without peeling the organic resin film from the glass substrate.

10‧‧‧Organic EL Panel

12‧‧‧Polyimide film

14‧‧‧ transparent electrode layer

16‧‧‧Light-emitting layer

18‧‧‧Sealing layer

20‧‧‧ Support glass

22‧‧‧ protective film

24‧‧‧Support substrate

30‧‧‧ Etching device

32‧‧‧ transport roller

34‧‧‧ spray unit

FIG. 1 is a diagram showing a configuration of a display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a manufacturing process of the display device.

FIG. 3 is a diagram showing an etching process of a display device.

FIG. 4 is a diagram showing an etching apparatus.

FIG. 5 is a view showing an etching process in another embodiment.

Hereinafter, a display device according to an embodiment of the present invention will be described using FIG. 1. FIG. 1 is a schematic side view of the organic EL panel 10. Organic EL panel The 10 series includes a polyimide film 12, a transparent electrode layer 14, a light emitting layer 16, and a sealing layer 18.

The polyimide film 12 is a substrate constituting the first main surface of the organic EL panel 10, and preferably has a thickness of 7 to 30 μm. Polyimide film 12 is an organic resin film corresponding to the scope of patent application. In this embodiment, polyimide is used as the organic resin film, but it is not particularly limited as long as it is a resin film that can withstand the processing temperature of the film formation process.

A transparent electrode layer 14 and a light-emitting layer 16 are sequentially laminated on the polyfluoreneimide film 12. For the transparent electrode layer 14, it is preferable to form a known low-temperature polycrystalline silicon film. The light emitting layer 16 is a functional layer including a hole transport layer, an organic EL element, and an electron transport layer. The transparent electrode layer 14 and the light-emitting layer 16 are display elements corresponding to patent applications. The sealing layer 18 is configured to cover the light emitting layer 16 and prevent the organic EL element and the like from being degraded by moisture or oxygen exposed to outside air. Generally, the sealing layer 18 is formed by laminating resin films having different compositions. In this embodiment, the film is sealed with five sealing layers, but the configuration of the sealing layer 18 can be changed as appropriate. The organic EL panel 10 is configured as a top-emission system in which a side view image is provided with a sealing layer 18 disposed.

Hereinafter, a method for manufacturing the organic EL panel 10 will be described using FIGS. 2 (A) to (C). First, as shown in FIG. 2A, a polyimide film 12 is formed on a support glass 20. The supporting glass 20 is a glass substrate having a thickness of 300 to 700 μm. For the supporting glass 20, alkali-free glass or soda-lime glass can be used, but it is not particularly limited. A polyimide precursor dissolved in a solvent such as dimethylacetamide or methylpyrrolidone is coated on the support glass 20. Polyimide precursor system can use slit coater or roller Coating is performed by a coating device such as a coater. At this time, it is preferable to apply so that the thickness of the polyimide film 12 becomes 7 to 30 μm. The polyimide precursor is hardened by being put into a drying furnace that has been heated to a predetermined temperature. In addition, it is also possible to form a primer layer for increasing the adhesion before the polyimide film 12 is coated on the supporting glass 20, or a resist for preventing the display element from being affected during the etching process described later. Barrier.

After the polyfluorene imine film 12 is formed, a transparent electrode layer 14 is formed on the polyfluorene imine film 12. In this embodiment, a low-temperature polycrystalline silicon film is formed on the polyimide film 12 by a known method such as sputtering. A light emitting layer 16 is formed on the transparent electrode layer 14 (see FIG. 2 (B)). The light emitting layer 16 can be formed into an organic material by a known method such as a vapor deposition method or an inkjet method. The light-emitting layer 16 includes not only a light-emitting layer obtained from an organic material but also a hole-transporting layer or an electron-transporting layer. In this embodiment, a hole-transporting layer is sequentially stacked on the transparent electrode layer 14 to emit light. Layer, electron transport layer.

The transparent electrode layer 14 and the light emitting layer 16 are covered by laminating a plurality of sealing layers 18 (see FIG. 2 (C)). The sealing layer 18 is a resin film having gas barrier properties, and is configured to have the airtightness and watertightness of the light emitting layer 16. The sealing layer 18 can protect the light emitting layer 16 more effectively by alternately laminating an inorganic film and an organic film. In this embodiment, the film is sealed with five sealing layers, but the laminated structure can be appropriately changed.

For the inorganic film in the sealing layer, silicon nitride, silicon oxide, silicon oxynitride, carbon oxide, carbon nitride, aluminum oxide, and the like can be used. For organic films, polyester, methacryl, methyl polystyrene, and transparent Fluorine resin, polyimide, polyurethane, cyclic olefin copolymer, acrylic resin, epoxy resin, etc. Among them, it is preferable that the sealing layers have a total light transmittance of 90% or more, so as to ensure the visibility of the display device.

Hereinafter, the removal process of the support glass 20 of the organic EL panel 10 sealed with a thin film is demonstrated using FIG.3 (A) and FIG.3 (B). Removal of the supporting glass 20 is performed by an etching process in which an etchant is brought into contact with the supporting glass 20.

First, before the etching process is performed, the sealing layer 18 is covered with a protective film 22. The protective film 22 is made of a member resistant to an etching solution, and has at least resistance to hydrofluoric acid. However, in this embodiment, the film member is used for protection, but it may be covered with an etching resist material. When the sealing layer 18 disposed on the outermost surface has resistance to hydrofluoric acid, the protective film 22 may not be used. In addition, if the adhesiveness of the protective film 22 is too strong, when the protective film 22 is peeled off after etching, the light emitting layer 18 may be peeled off at the same time. Therefore, it is preferable to arrange a release sheet (not shown) between the sealing layer 18 and the protective film 22 so that no load is applied to the light emitting layer 18 during peeling. For the release sheet, a film-like resin having no adhesive force can be used. When the release sheet is disposed, it is disposed only at the central portion of the organic EL panel 10, and the peripheral portion makes the sealing layer 18 and the protective film 22 in close contact.

In addition, as shown in FIG. 3 (A), it is preferable to cover the end surface of the organic EL panel 10 with a protective film 22. If the adhesion of the protective film 22 is insufficient, other protective members may be used for the end face protection. As for the protective member on the end face, it is an ultraviolet curing resin or a thermosetting resin which can make the appliance resistant to etching. If a resin material as shown above is used, the main body of the organic EL panel 10 After the protective film 22 is formed on the surface, a resin is applied to the end surface, and a hardening treatment is appropriately performed. The main surface of the organic EL panel 10 is protected by the polyimide film 12 and the sealing film 18, but there is a possibility that the protection against the intrusion of gas or moisture from the side is not sufficient. In particular, it is difficult to sufficiently protect the interface between the polyimide film 12 and the sealing layer 18. Therefore, it is preferable to perform protection using the protective member described above.

In order to etch the support glass 20, it is preferable to use the single-chip etching apparatus 30 shown in FIG. 4 (A). The etching device 30 includes at least a transport roller 32 and a spray unit 34. The transfer roller 32 is configured to be arranged along the longitudinal direction of the etching device 30 to transfer the organic EL panel 10. At this time, the supporting glass 20 is placed so as to be in contact with the transfer roller 32 (see FIG. 4 (B)).

The spray unit 34 is configured to be disposed below the conveyance roller 32 and sprays an etching solution toward the support glass 20. The spray unit 34 includes a plurality of spray nozzles so as to spray the etching solution uniformly on the support glass 20. As for the etching solution, it is preferred that the supporting glass 20 is dissolved but the polyimide film 12 is not dissolved. In this embodiment, an etching solution containing at least hydrofluoric acid is used. However, in addition to hydrofluoric acid, an inorganic acid such as hydrochloric acid or a surfactant may be added if necessary.

Among them, it is preferable that the spraying unit is configured to spray the cleaning liquid from the spray unit disposed near the carrying-in portion and the carrying-out portion of the etching apparatus, and the supporting glass 20 is washed. Although the cleaning liquid of this embodiment uses city water supply, it is not limited to this.

The support glass 20 which was put into the etching apparatus 30 was borrowed It is conveyed in the horizontal direction by the conveyance roller 32, and is etched by the etchant sprayed by the spray unit 34 while being sprayed. In this embodiment, an etching solution is sprayed from below on the support glass 20 arranged downward, thereby preventing the etching solution from contacting the organic EL panel 10 more than necessary. If the etchant comes into contact with the support glass 20, it will fall directly and be stored in a collection tank (not shown).

The spray pressure of the etchant or the distance between the spray unit 34 and the organic EL panel 10 can be appropriately adjusted so that the etchant does not scatter to areas other than the support glass 20. If the etchant contacts the organic EL panel 10 for a long time, the moisture of the etchant gradually penetrates, and the light emitting layer 16 may be deteriorated due to the moisture. Therefore, it is necessary to increase the number of layers of the sealing layer 18 in order to protect the light emitting layer 16 more securely, which may result in inconveniences such as excessive costs and increase in the thickness of the organic EL panel 10.

The supporting glass 20 is gradually reduced in thickness, and is etched until the polyimide film 12 is exposed as shown in FIG. 3 (B). During the etching process, the hydrofluoric acid concentration, ejection pressure, or conveyance speed of the etching solution is appropriately adjusted so that the timing at which the entire glass 20 is etched is the same as the timing at which the organic EL panel 10 is carried out by the etching device. In addition, since the organic EL panel 10 is transported while being supported by the transport roller 32 from below, it can be handled stably even if all the supporting glass 20 is dissolved.

Among them, the polyimide film 12 has resistance to hydrofluoric acid and high gas barrier properties. Therefore, even when the polyimide film 12 is exposed, the etching process is temporarily continued, and there is no polyimide film. When the amine film 12 is stained, the transparent electrode layer 14 or the light emitting layer 16 is protected. However, if there is a possibility of deterioration of the display element even in this case, A barrier layer is preferably formed between the amine films 12. With the laminated structure of the barrier layer and the polyfluorene film 12, the light emitting layer 16 can be more reliably protected. The barrier layer can be formed on the first main surface of the support glass 20 before the polyimide precursor is applied.

The protective film 22 is peeled after being subjected to an etching process. The protective film 22 can be peeled off by applying a physical force. If a resist material is used, it can be dipped in a peeling solution and peeled off, and it should be treated in a short time so as not to affect the display element. Among them, since the peripheral portion of the organic EL panel 10 is a non-product area that is removed in a later process, even when the end surface is protected with a resin or the like, it is not necessary to remove the protective material that is applied to the end surface after the etching process. .

In the event that the organic EL panel 10 is deformed during transportation due to the removal of the support glass 20, the ejection pressure of the etchant may be reduced or the interval between the transportation rollers 32 may be reduced. If it is difficult to adjust the etching apparatus, as shown in FIG. 5, a support substrate 24 having acid resistance may be disposed instead of the protective film 22. The support substrate 24 is designed to ensure the rigidity of the organic EL panel 10 even if the support glass 20 disappears. The support substrate 24 is thicker than the protective film 22 to prevent the organic EL panel 10 from being deformed during transportation. As the supporting substrate, a resin substrate coated with polyvinyl chloride or Teflon (registered trademark) with a thickness of 500 μm or more can be used. The support substrate 24 may be disposed on the protective film 22. The support substrate 24 is peeled by the organic EL panel 10 after the etching process.

The display devices shown above are generally manufactured in a state where a plurality of display devices are chamfered by a large substrate. At this time, after the etching process, a process of dividing the large substrate into individual substrates is performed. Break processing You can use a scribing device or laser device. The supporting glass 20 is removed by an etching process, and therefore, it can be easily broken even if a conventional laser device for cutting a conventional resin substrate is used.

In this configuration, it is also possible to manufacture a flexible display with little need to change a conventional manufacturing process. In addition, since the etching processing system hardly changes the processing time even if the size of the substrate is changed, the processing can be performed without reducing production efficiency when manufacturing larger substrates in the future.

It should be understood that all the descriptions of the above embodiments are examples and are not restrictive. The scope of the present invention is shown by the scope of patent application rather than the embodiments described above. In addition, the scope of the present invention is intended to include all changes within the meaning and scope equivalent to the scope of patent application.

10‧‧‧Organic EL Panel

12‧‧‧Polyimide film

14‧‧‧ transparent electrode layer

16‧‧‧Light-emitting layer

18‧‧‧Sealing layer

20‧‧‧ Support glass

22‧‧‧ protective film

Claims (2)

A display device manufacturing method is a display device manufacturing method for manufacturing a display device that uses a display element to display an image, and includes a step of forming an organic resin film on a first main surface of a glass substrate; and forming the organic resin film on the organic resin film. A step of forming a layer including a display element; and removing the glass substrate by etching the second main surface side while covering the first main surface side of the glass substrate including the organic resin film with an etching-resistant member. A step of. For example, in the method for manufacturing a display device according to the scope of claim 1, in the step of removing the glass substrate, an etching solution that dissolves the glass substrate but does not dissolve the organic resin film is used.